migration plan: record the confirmed provider tier and the snapshot gap

Nathan confirmed the new box is on Infomaniak VPS Cloud, not Lite. The distinction decides three things this plan depends on: Cloud carries a 99.99% SLA, resizes both ways, and includes one snapshot, whereas Lite has no snapshot and closes outbound 25 outright. Cloud opens port 25 on justified request, which is what to cite in the support thread. Recorded alongside it: no snapshot has been taken on the new box yet, which is worth doing before the wizard is submitted.

cloudron-server-migration.md

@@ -86,6 +86,15 @@ needed to restore are inside the thing being restored.
       `sudo cloudron-support --troubleshoot`. The version needs no guessing: a fresh install pulls the
       current release, which is 10.1.5 or newer, and anything ≥ 10.1.5 restores this backup.
       **Ports still to open on the new box (checked 2026-10-30): 25, 465, 587, 993, 995, 4190.** Only
+
+      **Provider tier — confirmed 2026-11-01: Infomaniak VPS Cloud** (not Lite; the two differ
+      in ways that matter here). What the tier provides, per Infomaniak's own product pages:
+      a **99.99% availability** commitment, **10 Gb/s** bandwidth, resizing **up and down**, and
+      **one snapshot included** (extensible) — so the snapshot question is answered, but **none
+      has been taken yet on the new box**: take one before submitting the Cloudron wizard, so
+      there is a known-good point to return to. The Lite tier, by contrast, has no snapshot, no
+      SLA, and closes outbound 25 outright; Cloud allows **port 25 "on justified request"**.
+      That last point is the one to cite if the Infomaniak support thread asks us to justify it.
       22, 80 and 443 answer today. Mail will not work on the new box until these are added, and
       outbound 25 is the separate Infomaniak ticket.
       **Leave for cutover day:** the domain, the plan/subscription (completing the wizard early can